1. Field of the Invention
The invention relates to a filter plate for a filter press on which a plurality of filter plates form filter chambers between each other and each support on one or on both of their sides a pressing diaphragm.
2. The Prior Art
Filter plates are known in a variety of designs, different techniques are employed for securing the pressing a diaphragm on the support wall. If the filter plate has a pressing diaphragm on both sides, another plate (for example a chamber plate), is usually arranged between the two filter plates.
The invention is based on the problem of improving these filter plates in such a way that the manufacturing process is simplified.
This problem is solved according to the invention in that the pressing diaphragm is provided with an edge strip that extends all around. The edge strip is welded to the support wall of the filter plate, whereby the edge strip, on its side facing away from the support wall, is provided with transversely extending cutouts. Provision is made between the edge strip and the plate frame for a filtrate channel into which filtrate drain ducts feed, these ducts lead to the filtrate outlet.
An advantage of this invention is that the pressing diaphragm can be uniformly manufactured in one single production step since the dimensions of the edge strip substantially correspond with the profiled projections, therefore pre-fabrication of the edge strip is omitted. The pressing diaphragm is molded directly, for example from granulate material. Since the filtrate channel is arranged outside of the pressing diaphragm, there is no risk that damage will occur to the diaphragm when the filtrate channel is milled for removing the welding flash, or when the filtrate drain channels are drilled. The manufacture of the filter plate is therefore reduced to prefabrication of the support wall with the plate frame, which is usually carried out by pressing or machining. The pressing diaphragm can be produced in one manufacturing step from granulate, so that the pressing diaphragm subsequently only needs to be welded to the support wall. The filtrate channel is produced automatically in accordance with the measurements selected for the pressing diaphragm.
Furthermore, an advantage of the present invention is that the filtrate channel can be provided with an adequate depth because the filter cloth will not get lodged in the filtrate channel, thereby obstructing the off-flow of the filtrate.
According to a preferred embodiment of the invention, the height of the edge strip substantially equals the height of the profiled projections on the edge strip. However, the height of the projections can be slightly greater.
In a first embodiment of the invention, the top sides of the edge strip and the plate frame are disposed in one common plane. Furthermore, the filtrate drain ducts are in the form of bores feeding into the bottom of the filtrate channel.
However, it is also possible that the top side of the edge strip extends offset in the direction of the support wall relative to the top side of the plate frame. The filtrate drain ducts feed into cutouts disposed in the edge strip.